Yarn manufacture and products obtained thereby



United States Patent M 3,113,369 YARN MANUFACTURE AND PRODUCTS QBTATNEDTHEREBY Homer D. Barrett, Robert T. Estes, and George C.

Stow, In, Decatur, Ala, assignors, by mesne assignments, to MonsantoChemical Company, a corporation of Delaware No Drawing. Filed May 2,1%0, Ser. N 25,962. 14 Claims. (Cl. 28-75) This invention relatesgenerally to an improved method for producing organic filamentarymaterials and to improved products resulting therefrom. Moreparticularly, it relates to an improved method for producing filamentsand yarns from synthetic linear superpolymers and to cabled structuresembodying the filaments and yarns produced in accordance therewith.

In the manufacture of filament yarns from such syn thetic linearpolymers as the polyamides, polyesters, polyalkylenes, polyurethanes,polycarbonates and acrylouitrile polymers, it has been known thatultimate yarn tenacity can be greatly increased by employing thetechnique of drawing, which comprises stretching the yarn filamentsafter their formation to increase molecular orientation.

Although the drawing operation can be conducted by various means, acommon procedure is to employ two filament advancing devices generallyknown as a feed roll and draw roll. Filament stretching is achieved byrunning these rolls at differential speeds with the amount of stretchingor drawing being determined by the ratio of the peripheral speeds of thetwo rolls. In order to localize the point at which stretching occurs, abraking device is sometimes placed between the feed roll and draw roll.Generally, the braking device consists of a pin, called the draw pinaround which the yarn is wrapped a number of times. The draw pinintroduces frictional drag on the moving filaments which causesstretching to take place in the area of the draw pin. The introductionof frictional drag to localize stretching is utilized in those instanceswhere there is a tendency for non-uniform drawing to occur since greateruniformity can be obtained by employing this procedure.

It has been known that the drawing operation can sometimes befacilitated when the yarn temperature is elevated during drawing. Theheating may be carried out by inserting a hot pin, a hot plate, or hotfluid bath between the feed roll and draw rolls of the drawing apparatusor by using a heated feed roll. Elevated temperatures are effectivebecause intermolecular forces are diminished by the resulting increasein molecular activity, and therefore the ratio of the force required todraw the yarn to that required to break it is lessened. Permissibletemperatures which may be used in hot drawing vary somewhat with thenature of the polymer from which the yarn is formed, since the maximumtemperature which can be employed is limited by the polymer meltingpoint. It is a common practice to employ a hot drawing technique whenprocessing yarn for use in products which require great tensilestrength, as for example in the manufacture of reinforcement cords forinflatable tires.

A particularly troublesome problem encountered when drawing at eitherambient or elevated temperatures is the occurrence of filament breakageduring the drawing operation. Thus, at times one or more individualfilaments in the thread line may break and wrap around the draw roll oras sometimes happens the entire thread line may break, in which caseproduction is stopped until adjustments can be made. Such filamentbreakage not only affects labor requirements and productivity, but theproduct quality is also affected in an adverse manner.

The principle cause of filament breakage while drawing is the build-upof excessive tension on the yarn which in 3,113,359 Patented Dec. 10,1963 turn is caused, for the most part, by inter-filament friction andby the generation of excessive friciton as the yarn passes over the drawpin when such device is employed.

It is known that excessive yarn tensions resulting from the developmentof unduly high frictions during drawing can be reduced by applying tothe yarn various antifriction conditioning agents before it is drawn.These agents are generally applied from an aqueous vehicle rather thanfrom non-aqueous systems to afford a more uniform distribution andbetter control over the amount of active agent which is deposited on theyarn. These factors are of considerable importance and cannot becontrolled when a non-aqueous solvent, for example, is employed as avehicle. Non-aqueous solvents are highly objectionable because of thehigh solvent retention on the yarn and a resulting serious impairment ofthe drawing operation.

Although the tendency for excessive yarn tensions to develop duringdrawing can be reduced somewhat by pretreatment with certian knownconditioning agents of the pri r art, there is a continuing need fortreating compositions which are capable of greater elfectiveness incoping with the problem.

It has now been found that the build-up of excessive yarn tensionsduring drawing can be greatly minimized by applying a wax-containingaqueous emulsion to the yarn before it is drawn. It has further beenfound that this procedure not only facilitates the drawing operation,but that in addition thereto substantial advantages are imparted to theultimate yarn product. For example, products such as various types ofrope and rubber reinforcement cords have shown extraordinary increasesin flex life when produced from yarns treated in this manner.

As is well known filamentary materials formed from synthetic linearpolyamides, polyesters, polypropylene and like synthetic linear polymersare commonly used in the production of cabled structures such as ropeand various ty e cords which are used to reinforce rubber products suchas, for example, rubber tires, transmission belts, hose and the like.These cabled structures are generally made by twisting and plyingtogether one or more strands of yarn each of which have been previouslysubjected to a drawing operation in accordance with the procedure asdescribed hereinabove. Although cord structures manufactured fromsynthetic linear ploymers are employed as reinforcing materials in awide variety of ruber products, an exceptionally large market hasdeveloped in the pneumtaic tire field. At present virtually all aircraftand large oif-the-road equipment tires are reinforced with such cord aswell as substantially all of the premium passenger car tires in additionto a large percentage of automobile replacement tires. All such cords orfabrics are subjected to more or less severe flexing during service, andfor a more satisfactory performance the cord structure should have ahigh flex life at elevated temperatures. There has been an existing needfor improvement in these respects for all presently available tire cordproducts.

Accordingly, an object of this invention is to improve the process stepof drawing synthetic linear polymers.

Another object of the present invention is to provide a method forproducing improved cabled structures from synthetic linear polymericmaterials.

A further object of this invention is to provide a method for producingsuperior reinforceemnt cords for rubber structures from synthetic linearpolymeric materials.

A still further object of the present invention is to provide a methodfor producing tire cord for use in reinforcing infiatable rubber tireshaving a greater resistance to compression-extension fatigue andconsequently an increased flex life.

Gther objects and advantages will become readily apparent in thedescription immediately following.

As has been noted, the objects of this invention are achieved bytreating synthetic polymeric filaments before they are drawn with acomposition which contains a wax as the essential element. In additionto the essential wax component, one or more emulsifying agents and anaqueous vehicle are included as part of the treating composition. Alubricant such as mineral oil, fatty acid esters and the like may alsobe added if desired.

The wax component may be selected from a wide variety of waxes. Thus,for example, there may be employed japan wax, ceresin, carnauba,candelilla, ozocerite, montan wax, parafiin waxes, microcrystallinewaxes or any other natural wax. The various synthetic waxes, such as,the phthalimides, polymers of ethylene oxide such as Carbo wax,terphenyls such as Santowax, the polyalkylenes such as polyethylene mayalso be employed with good results. The waxes may be oxidized ornon-oxidized and should preferably have a melting point of between 50 C.to 140 C. and a penetration at 77 F. of between 1 and in accordance withASTM test method D-l321-55T. Additional properties that are desirablebut not critical when employing oxidized waxes are an acid number ofbetween 10 and 50 and a saponification number of between 30 and 100.

Among the many waxes that have been found suitable, best results areachieved with microcrystalline waxes. Microcrystalline waxes are thosewaxes which have a finer, less apparent crystalline structure thanparafiin wax and which comprise a solid hydrocarbon mixture of molecularweight averaging higher than paraflin wax. These waxes possess plasticproperties and are obtainable from crude petroleum fractions. Allmicrocrystalline waxes are of about the same molecular weight and aresaid to be composed of hydrocarbon chains of twice the length of thoseof the microcrystalline waxes. Commercially available products areexemplified by Crown Wax 23, Crown R50, Bareco Wax C-750O and C-6500 ofthe Petrolite Chemical Corporation, and Cardis 320, Mekon Y-20 andFortex of the Warwick Wax Company.

Any of the known emulsifying agents, which are capable of dispersing waxin an aqueous medium to form an emulsion which is stable over extendedperiods of time and at elevated temperatures, may be employed in thepractice of this invention. While a number of available emulsifiers canbe employed, the amine soaps are particularly suitable. The amine soapmay be derived from a fatty acid containing at least about 8 carbonatoms with from about 12 to 22 carbon atoms being preferred. Oleic acidis highly suitable, but such fatty acids as lauric, palmitic, myristic,stearic, behenic and the like may be used if desired either in whole orin part. Animal, marine and vegetable oils are suitable sources for thefatty components of these soaps. Any water-soluble aliphatic amine maybe employed in forming the soap, but the lower alkylolamines arepreferred as exemplified by the primary, secondary, and tertiary aminesof ethanol, propanol, isopropanol and the several butanols.Triethanolamine and Z-amino 2-methyl l-propanol are particularlyoutstanding for this purpose. Other suitable amines include the variousprimary, secondary and tertiary methyl, ethyl, propyl, isopropyl andbutyl amines and morpholine. The amine soaps may be either prepared inadvance or in situ by the addition of the amine and an appropriate fattyacid to the aqueous vehicle.

It is often desirable to include a non-ionic surface active agent as apart of the emulsifying system in that these materials tend to suppressthe accumulation of static during the drawing operation in addition toproviding increased emulsion stability. Among agents of this type whichmay be employed are the polyoxyethylene ethers of a long chain fattyalcohol or thiol and the polyoxyethylene esters derived from long chainfatty acids. The long chain fatty alcohols and long chain fatty acidsfrom which these materials are formed may contain from about 12 to 40 boatoms in their alkyl chains and these chains may be straight orbranched. The fatty acids and fatty alcohols may be commercially puresingle compounds or mixtures of such single compounds of one type, ieacids or alcohols, or they may be mixtures that are obtained fromnaturally occurring products. Suitable long chain fatty alcohols are,for example, dodecyl alcohol, tri

decyl alcohol, cetyl alcohol, myristyl alcohol, linoleyl alcohol and themixture of alcohols derived from sperm oil. The alkylated phenols suchas octyl phenol and nonyl phenol may also be employed. Suitable longchain acids are, for example, lauric acid, oleic acid and the mixture ofacids derived from cocoanut oil. In producing the polyoxyethylene ethersand esters, ethylene oxide may be permitted to act directly on the longchain fatty alcohols and long chain fatty acids. Alternatively, the longchain fatty acids and long chain fatty alcohols may be reacted with apolyethylene glycol. The length of the polyethylene oxide chain may bevaried over a considerable range, satisfactory results having beenobtained with chain lengths of from about 2 to 50 ethylene oxide units.A particularly effective non-ionic emulsifier of this type is the adductformed by reacting 1 mol of tridecyl alcohol with an average of 9 molsof ethylene oxide.

As has been indicated, a lubricating oil may be included as a part ofthe yarn treating compositions of this invention. The oils may be ofvegetable, marine, or of petroleum origin. Among the vegetable oils,there may be mentioned linseed, soybean, corn, peanut, castor, rapeseedand olive oils. Suitable marine oils are menhaden oil, whale oil andsperm oil. Applicable mineral oils are those whose viscosities varybetween the kerosenes and the heavy motor oils with a highly refined,colorless mineral oil being preferred. Mineral oils having Sayboltviscosities of from 30 to 180 seconds at F. are considered of especialadvantage. Various of the so-called synthetic lubricants-may also beused to advantage. Among the synthetic lubricating oils which can besuitably employed are the various polyalkylene glycols, commerciallyavailable from the Carbide and Carbon Chemical Company and knowncommercially as Ucons. In addition, the fatty acid esters can be used toadvantage. The esters may be either mono-, di-, triesters, etc., ormixtures thereof. The fatty acid portion of the ester can containanywhere from 1 to about 22 carbon atoms; and may be derived from suchfatty acids as acetic, propionic, lauric, myristic, palmitic, stearic,adipic, azelaic, benzoic, citric, abietic, fumaric, phthalic, oleic,ricinolec, sebacic, succinic, tartaric, etc. The alcohol portion may bederived from either monohydric or polyhydric alcohols which contain from1 to 12 carbon atoms. Suitable examples are methanol, ethanol, Z-methyll-propanol, l-pentanol, heptanol, glycerol, hexitol, sorbitol, mannitol,pentaerythritol and many others. Among specific examples of suitableesters are isopropyl palmitate, butyl stearate, isopropyl myristate,isobutyl laurate, methyl abietate, dibutyl adipate, di-isooctyl adipate,di-2-ethylbutyl azelate, glycerol monoacetate, glycerol tripropionate,di-n-butyl maleate, n-propyl oleate, amyl oleate, isopropyl palmitate,isooctyl palmitate, dimethyl phthalate, butyl octyl phthalate, di(2-ethylhexyl) phthalate, isobutyl ricinoleate, glycerolmonoricinoleate, dioctyl sebacate, n-butyl stearate, octyl stearate,dibutyl succinate, diethyl tartrate, sorbitol tetrastearate, sorbitanmonopalmitate, etc. A class of fatty acid esters which are particularlyadvantageous are mixed triglycerides which may be represented by thefollowing formula:

RCOOOHa RCOOGH RCOOCH:

wherein R designates saturated or unsaturated aliphatic radicals. Eitherone or two of the R groups contain from 1 to 5 carbon atoms having atmost one double bond while the remaining R group or groups may containfrom 12 to 22 carbon atoms with from 0 to 5 double bonds.

The location of the shorter carbon chain aliphatic radicals with respectto the glyceryl radical is not of critical importance, i.e. it may be ineither the alpha, beta or gamma position. Some examples of suitablecompounds of this type are glycerol mono-ricinoleate di-acetate,glycerol mono-linoleate di-acetate, glycerol mono-linolenate diacetate,glycerol mono-acetate di-linoleate, glycerol monoacetate di-ricinoleate,glycerol mono-laurate di-butyrate, glycerol mono-laurate di-valerate,etc. Various phosphoric acid derivatives may also be suitably employed.Examples of such compounds include triethyl phosphate, tributylphosphate, triphenyl phosphate, tri-(2-ethylhexyl) phosphate,tributoxyethyl phosphate, tricresyl phosphate, cresyl diphenylphosphate, tri-dimethylphenyl phosphate, diphenyl mono-o-xenylphosphate, trip-tert-butylphenyl phosphate, diethyl ethylphosphonate,dibutyl butylphosphonate, bis (Z-ethylhexyl) 2-ethylhexylphosphonate,tris (2-chloroethyl) phosphite, etc.

The aqueous emulsions which are used in the practice of this inventioncan contain up to 30 percent solids by weight without exceeding theviscosity limits normally used for conditioning agents used in yarnproduction, with from about to percent solids being generally preferred.By the term solids as used herein, there is meant the totality ofingredients exclusive of the aqueous vehicle without regard to physicalstate. The solids may contain from 10 to 90 percent by weight of theessential wax ingredient and from 10 to 90 percent total of one or moreemulsifying agents. In those instances where a mineral oil or otherlubricating oil, such as described hereinabove, is employed, thiscomponent may be present in an amount constituting up to 80 percent byweight based on the total weight of the solids present.

Conventional methods can be employed in formulating the aqueousemulsion. A simple and convenient method is to merely heat the solidmaterials together until melted into a blend and then add the moltenblend of ingredients to the aqueous vehicle with vigorous mechanicalagitation. During this addition step, the water should be maintained atan elevated temperature which is near to or at the boiling point.

Generally, good results are obtained in both cold and hot drawingoperations when the conditioning agent is applied in an amount such thatthe solids deposited on the yarn constitute from about 0.1 to about 2.0percent based on the weight of the yarn. Although lesser or greateramounts may be used best results are obtained when the amount of solidsdeposited on the yarn is within this range.

As has been emphasized, the above-described treating agent is applied tothe filaments or yarn prior to drawing. A conventional and convenienttechnique of application is to contact the yarn while moving oradvancing in the course of production with a roll which is made torotate so that its lower portion dips into a pan containing the treatingcomposition. The treating agent is pumped from a reservoir to the pan orother container and a constant level is maintained by an overflow pipeor similar device. Other suitable methods and devices may be employedsuch as the use of a wick or split roll or the yarn may be passedthrough a bath containing the treating agent.

The following examples specifically illustrate the manner in which theprocess of the present invention is conducted and the advantagesobtained thereby. That is, advantages which accrue both with respect toimprovement in the drawing operation as well as in the ultimate yarnproducts. The examples are given by way of illustration only and are notto be construed as limitative.

Example I A bundle of filaments, comprising 140 in number and having atotal denier of 4500 was formed by the melt extrusion of apolyhexamethylene adipamide polymer, commonly known as nylon 66. Thethus formed filaments were then brought together in the form of a yarnwhich was treated with an aqueous emulsion which contained 12 parts byweight of solids. The solids content consisted of 33 parts by weight ofa microcrystalline wax with a melting point of between and C., 25 partsby weight of a mineral oil having a Saybolt viscosity of 50 seconds at100 F., 17 parts by weight of the amine soap formed from stoichiometricamounts of 2-amino 2-methyl 1-propanol and oleic acid, and 25 parts byweight of the adduct formed by reacting 1 mol of tridecyl alcohol with 9mols of ethylene oxide. The treating agent was applied by means of arotating roll in an amount such that 0.39 percent solids were depositedon the yarn, based on the weight of the yarn. The yarn was then taken upon a spin bobbin from where it was passed to a conventional drawtwistmachine where it was hot drawn to a tenacity of 8.54 grams per denier.For purposes of evaluating the drawtwist performance the number ofthread line breaks and draw roll wraps (broken filaments wrapped on thedraw roll) were determined and recorded.

Example 11 A multi-iilament yarn comprising a bundle of filaments andhaving a total denier of 4500, was formed by the melt extrusion of apolyhexamethylene adipamide polymer. The yarn was then treated with anaqueous emulsion which contained 12 parts by weight of solids. Thesolids content consisted of 33 parts by weight of a microcrystalline waxwith a melting point of between 100 C. and 105 C.; 25 parts by weight ofa mixture of triglycerides consisting chiefly of glycerolmono-ricinoleate di-acetate, with glycerol mono-linoleate di-acetate,and glycerol mono-linolenate di-acetate in considerably smaller amounts,the mixed esters being obtained from the monoesterification of glycerolwith castor oil acids and further di-esterified with acetic acid; 17parts by weight of the amine soap formed from stoichiometric amounts of2- amino 2-methy1 1-propanol and oleic acid, and 25 parts by weight ofthe adduct formed by reacting 1 mol of tridecyl alcohol with 9 mols ofethylene oxide. The treating agent was applied by means of a rotatingroll in an amount such that 0.39 percent solids were deposited on theyarn, based on the weight of the yarn. The yarn was then taken up on aspin bobbin from where it was passed to a conventional drawtwist machinewhere it was hot drawn to a tenacity of 8.54 grams per denier. As isExample I, the thread line breaks and draw roll wraps were noted andrecorded.

Example 111 Yarn identical to that described in Example I and Example IIwas impregnated before being drawn with a commercially used conditioningagent having a combination of sulfonated peanut oil and a mineral oil asessential components. The application was made in an amount such that0.85 percent solid material, based on the weight of the yarn wasdeposited thereon. The yarn was then hot drawn under the identicalconditions which were employed in Example I and Example II and to atenacity which was of substantially the same value.

Drawing performance data wherein Examples 1, II and III are comparedfrom the standpoint of the occurrence of filament breaks and draw rollwraps is given in the following table. Since Example HI was in essence acontrol, it is so designated.

It is readily apparent from the above data that the conditioning agentsof this invention improve the drawing operation to an extent which iseven greater than that of one of the most efiective of such agents inthe prior practice. Although a hot drawing procedure with high denieryarn has been used for illustrative purposes in the above examples,equally good results are obtainable with lower denier yarns and indrawing at ambient temperatures.

As has been noted hereinabove, the practice of this invention not onlyfacilitates the yarn drawing process step, but surprising andoutstanding improvements in ultimate products are also realized.Examples of ultimate products which are greatly improved when producedfrom yarn which has been processed in accordance with this invention arethose which are subjected to compression and/or extension strains duringservice such as, for example, supporting cables, fish nets, rope,reinforcement cords for rubber structures including pneumatic tires,conveyor belts, power transmission belts, steam hose and various othercabled structures. The product advantages are illustrated in thefollowing examples.

Example IV Yarn produced from a polyhexamethylene adiparnide polymer andhaving a drawn denier of 840/ 140 was impregnated before drawing withone of the better commercial conditioning agents to the 1.45 percentlevel based on the weight of yarn. The yarn was then hot drawn at astandard draw ratio for tire cord and thereafter twisted and plied intoa cord structure.

Example V Yarn produced from a polyhexamethylene adipamide polymer andhaving a drawn denier of 840/ 140 was impregnated prior to drawing withan aqueous emulsion having a solids content consisting of 33 parts byweight of a microcrystalline wax having a melting point of from about100 C. to 105 C., 25 parts by weight of a mineral oil having a Sayboltviscosity of 50 seconds at 100 F., 17 parts by weight of the amine soapformed from equivalent weights of 2-arnino Z methyl 1-propanol and oleicacid, and 25 parts by weight of the adduct formed by the reaction of 1mol of tridecyl alcohol with 9 mols of ethylene oxide. The amount ofsolids deposited on the yarn was at a level of 0.56 percent based on theweight of the yarn. The yarn was then drawn at an elevated temperatureto a standard draw ratio for tire cord and thereafter twisted and pliedinto a cord structure.

Example VI Yarn produced from a polyhexamethylene adipamide polymer andhaving a drawn denier of 840/140 was impregnated prior to drawing withan aqueous emulsion having a solids content consisting of 33 parts byweight of a microcrystalline wax with a melting point of from about 100C. to 105 C., 25 parts by weight of a mineral oil having a Sayboltviscosity of 50 seconds at 100 F, 34 parts by weight of the amine soapformed from equivalent weights of 2-amino 2-methyl 1-propanol and oleicacid, and 8 parts by weight of the adduct formed by the reaction of 1mol of tridecyl alcohol with 9 mols of ethylene oxide. The amount ofsolids deposited on the yarn was at a level of 0.40 percent based on theWeight of the yarn. The yarn was then hot drawn to a standard draw ratiocustomarily used for tire cord and thereafter twisted and plied into acord structure.

Example VII Yarn produced from a polyhexamethylene adipamide polymer andhaving a drawn denier of 840/140 was impregnated prior to drawing withan aqueous emulsion hav: ing a solids content consisting of 33 parts byweight of a microcrystalline wax with a melting point of between 100 C.and 105 C.; 25 parts by weight of a mixture of triglycerides consistingchiefly of glycerol mono-ricinoleate diacetate with minor amounts ofglycerol mono-linoleate di-acetate and glycerol mono-linolenate, themixed tr-iglycerides being obtained by a first esterification ofglycerol 1 1, astor oil acids followed by further esterification withacetic acid; 17 parts by weight of the amine soap formed fromstoichiometric amounts of 2-amino 2-methyl l-propanol and oleic acid;and 25 parts by weight of the adduct formed by reacting 1 mol oftridecyl alcohol with 9 mols of ethylene oxide. The amount of solidsdeposited on the yarn was at a level of 0.39 percent based on the weightof the yarn. The yarn was then hot drawn to a standard draw ratio fortire cord and thereafter twisted and plied into a cord structure.

The tire cords of the above examples were built into the walls ofpneumatic rubber tires in accordance with the conventional procedure.The tires were inflated to 30 p.s.i.g. maximum pressure and thensubjected to the well known wheel test which comprises running a tireunder a given load against a belt to simulate road conditions. A 1585lb. load was employed while the wheel was run at a speed equivalent to45 mph. with the room temperature being maintained at F.

In the following table, a comparison is made of the results obtained byrunning the above described test tires until cord failure occurred. Eachof the mileage figures given in the table is the average obtained fromfour tires run to cord failure.

It is seen in the above test results, that the tires which containedreinforcement cords produced in accordance with this invention exceededthe performance of tires reinforced with cords produced in aconventional manner by a totally unexpected factor of approximately 3times or better. This is even more surprising when it is considered thatreinforcement cords of the test control tires contained in excess of 2.5times the amount of treating agent present on the reinforcement cords ofthe tires corresponding to the test examples of the present invention.Equally good results were realized with tires having reinforcement cordsderived from other synthetic liinear polymeric materials and wherein thecords were processed in the manner of this invention. For example, tirecords obtained from a polyvinyl alcohol polymer and treated inaccordance with this invention were built into the walls of inflatablerubber tires.- These tires were then tested against a control by theprocedure as described above.

It was found that the test tires exceeded the performance of the controlby a factor of from 2 to 2.5 times. That is, the test tires ran adistance of more than twice that of the control before cord failureoccurred. Similar tests were conducted on tires containing reinforcementcords obtained from a synthetic linear polyester, i.e. polyethyleneterephthalate and comparably excellent results were realized. It is,therefore apparent that the tire cord yarn produced in the manner ofthis invention possesses a greatly increased flex life, in fact, thatthe flex life of the yarn often exceeds the useful life of the tirewhich may end due to failure from other causes.

In addition to having the capacity to withstand the repeated flexing towhich the tire is normally subjected in the course of its use, it isalso important that reinforcement cords for tires and other products becapable of satisfactory adherence to the rubber structure.

When reinforcing cords are used in the fabrication of rubber productssuch as tires, it is common practice to dip the cord in a rubber bondingcomposition, such as a resorcin-formaldehyde latex formulation prior toits incorporation in the rubber tire. This operation is performed topromote better adhesion between the cord structure and the rubber tirecarcass. Due to the aqueous nature of the latex dip solution and forseveral other reasons, many yarn treating agents interfere with theabsorption of the proper amount of latex solution by the cord structureand they are said to have poor dip takeup characteristics. The cordstructures of this invention, however, have completely satisfactory diptake-up characteristics and adhere remarkably well to the tire or otherrubber structures in which they are incorporated.

Although the invention has been described herein with a greaterparticularity in connection with filaments, yarn cord structures, etc.which have been formed from a polyhexamethylene adipamide polymer, thiswas done merely to convenience and simplify illustration, for theinvention is fully applicable to filamentary materials which comprise awide variety of synthetic polymeric substances. These include, forexample, the full range of polycarbona-mides, e.g. polyhexamethyleneadipamide, polyhexamethylene sebacamide, polyoctamethylene adipamide,polyoctamethylene sebacamide, the self polymerization product of6-aminocaproic acid and also omego-aminoundecanoic acid, polypyrrolidoneand others in addition to the many copolymers thereof; the syntheticlinear polyesters, e.g. polyethylene terephthalate and the polyesterderived from the reaction of terephthalic acid andtrans-bis-1,4-(hydroxymethyl) cyclohexane, and various modifiedpolyesters; the hydrocarbon polymers, e.g. polyethylene, polypropylene,the vinylidine and styrene polymers; the acrylonitrile polymers andcopolymers thereof, e.g. the copolymers of acrylonitrile and vinylacetate; the polyurethanes; the polycarbonates; the polyvinyl alcoholsand many others.

As various changes and modifications of the invention can be madewithout sacrificing any of its advantages and without departing from thescope and spirit thereof, it is to be understood that all matter hereinis to be interpreted strictly as illustrative; and that the onlylimitations on the invention are those which appear in the followingappended claims.

We claim:

1. An improved method for imparting molecular orientation to filamentsformed from synthetic linear polymers comprising the steps ofimpregnating said filaments prior to the conduct of a drawing operationwith a wax-containing aqueous emulsion and thereafter drawing the thusimpregnated filaments to impart molecular orientation thereto.

2. The method of claim 1 wherein said wax is microcrystalline wax.

3. An improved method for imparting molecular orientation to filamentsformed from synthetic linear polymers comprising the steps ofimpregnating said filaments prior to a drawing operation with an aqueousemulsion containing up to 30 parts by weight of solids, said solidscomprising from about 10 to 90 parts by weight of a Wax, up to about 80parts by weight of another lubricant and from about 10 to 90 parts byweight of an emulsifying agent, and thereafter drawing the thusimpregnated filaments to impart molecular orientation thereto.

4-. The mehod of claim 3 wherein said filaments have been formed from apolyamide polymer.

5. An improved method for imparting molecular orientation to polyamidefilaments comprising the steps of impregnating said filaments prior tothe conduct of a drawing operation with an aqueous emulsion containingfrom about 10 to 15 parts by weight of solids, said solids consisting offrom about 10 to 75 parts by weight of a microcrystalline wax, fromabout 5 to 65 parts by weight of a fatty acid ester wherein the fattyacid portion of said ester contains from about 1 to 22 carbon atoms andthe alcohol portion from 1 to 12 carbon atoms, from about 7 to 50 partsby weight of the amine soap formed from stoichiometric quantities of2-amino 2-methyl 1-propanol and oleic acid, 5 to 40 parts by weight ofthe adduct formed by condensing 1 mol of tridecyl alcohol with 9 mols ofethylene oxide, said solids being deposited in an amount of from about0.1 to 2.0 percent by weight based on the weight of said filaments, andthereafter drawing the thus impregnated filaments to impart molecularorientation thereto.

6. An improved method for producing cabled structures from syntheticlinear polymeric filaments comprising 10 the steps of impregnating saidfilaments prior to the conduct of a drawing operation with awax-containing aqueous emulsion; drawing the thus impregnated filamentsto impart molecular orientation thereto and thereafter plying aplurality of said filaments into a cabled structure.

7. An improved method for producing reinforcement cords for rubberstructures from synthetic linear polymeric filaments comprising thesteps of impregnating said filaments prior to the conduct of a drawingoperation with a wax-containing aqueous emulsion; drawing the thusimpregnated filaments to impart molecular orientation thereto andthereafter plying a plurality of said filaments into a cord structure.

8. A composite product comprising a rubber composition and areinforcement cord in adhering relation therewith, said reinforcementcord being produced from a plurality of synthetic linear polymericfilaments in accordance with the method of claim 7.

9. A pneumatic tire which comprises rubber and reinforcing cords, saidcords being produced from a plurality of organic filaments in accordancewith the method of claim 7.

10. An improved method for producing reinforcement cords for rubberstructures from synthetic linear polymeric filaments comprising thesteps of impregnating said filaments prior to the conduct of a drawingoperation with an aqueous emulsion containing from about 10 to 15 partsby weight of solids, said solids consisting of from about 10 to 15 partsby weight of a microcrystalline wax having a melting point in the rangeof from 50 C. to 140 C., from about 5 to 65 parts by weight of alubricant selected from the group consisting of a fatty acid esterwherein the fatty acid portion of said ester contains from about 1 to 22carbon atoms and the alcohol portion from 1 to 12 carbon atoms and amineral oil having a Saybolt viscosity of 50 seconds at F., from about 7to 50 parts by weight of the amine soap formed from stoichiometricquantities of 2-amino 2-methyl 1-propanol and oleic acid and from about5 to 40 parts by Weight of the adduct obtained by reacting 1 mol oftridecyl alcohol with 9 mols of ethylene oxide, said solids beingdeposited in an amount of from 0.1 to 2 percent by weight based on theweight of the filaments; drawing the thus impregnated filaments toimpart molecular orientation thereto and thereafter plying a pluralityof said filaments into a cord structure.

11. A composite product comprising a rubber composition and areinforcement cord in adhering relation therewith, said reinforcementcord being produced from a plurality of synthetic linear polymericfilaments in accordance with the method of claim 10.

12. A pneumatic tire which comprises rubber and reinforcing cords, saidcords being produced from a plurality of synthetic linear polymericfilaments in accordance with the method of claim 10.

13. An improved method for producing reinforcement cords for rubberstructures from polyamide filaments comprising the steps of impregnatingsaid filaments prior to the conduct of a drawing operation with anaqueous emulsion containing from about 10 to 15 parts by weight ofsolids, said solids consisting of 33 parts by weight of amicrocrystalline wax with a melting point of between 100 C. and C., 17parts by weight of the amine soap formed from stoichiometric quantitiesof 2-amino 2-methyl 1-propanol and oleic acid, 25 parts by weight of amineral oil having a Saybolt viscosity of 50 seconds at 100 F., and 25parts by weight of the adduct formed by condensing 1 mol of tridecylalcohol with 9 mols of ethylene oxide, said solids being deposited in anamount of from 0.1 to 2 percent by weight based on the weight of thefilaments; drawing the thus impregnated filaments to impart molecularorientation thereto and thereafter plying a plurality of said filamentsinto a cord structure.

14. An improved method for producing reinforcement cords for rubberstructures from polyamide filaments 1 1 comprising the steps ofimpregnating said filaments prior to the conduct of a drawing operationwith an aqueous emulsion containing from about 10 to 15 parts by weightof solids, said solids consisting of 33 parts by weight of amicrocrystalline wax with a melting point of between 100 C. and 105 C.,17 parts by weight of the amine soap formed from stoichiometricquantities of 2-arnino 2-methy1 1-propanol and oleic acid, 25 parts byweight of a mixture of triglycerides consisting chiefly of glycerolmono-ricinoleate di-acetate with minor amounts of glycerolmono-linoleate di-acetate and glycerol mono-linoleate di-acetate, saidtriglycerides being obtained by a first mono-esterificationj of glycerolwith castor oil acids followed by a further esterification with aceticacid, and 25 parts by Weight of the adduct formed by condensing 1 mol oftridecyl alcohol with 9 mols of ethylene oxide, {said solids beingdeposited in an amount of from 0.1 to Zp'ercerit'by weight based on theweight of the filaments; drawing the thus impregnated filaments toimpart molecular orientation thereto and thereafter plying a pluralityof said filaments into a cord structure.

References Cited in the file of this patent UNITED STATES PATENTS MeyerJune 29, Whitehead Jan. 12, Brownell Mar. 30, Myers Jan. 29, Freund Apr.15, Ambelong Jan. 27, Schlatter et al. Dec. 29, Fortess et al. Jan. 10,Sonnenschein Mar. 25, Tompkins June 10, Fortess et a1. Sept. 23,Chandler Dec. 23, Wentworth Dec. 13, Fronmuller et al. Mar. 7,MacCormack July 4,

FOREIGN PATENTS Great Britain June 29,

1. AN IMPROVED METHOD FOR IMPARTING MOLECULAR ORIENTATION TO FILAMENTSFORMED FROM SYNTHETIC LINEAR POLYMERS COMPRISING THE STEPS OFIMPREGNATING SAID FILAMENTS PRIOR TO THE CONDUCT OF A DRAWING OPERATIONWITH A WAX-CONTAINING AQUEOUS EMULSION AND THEREAFTER DRAWING THE THUSIMPREGNATED FILAMENTS TO IMPART MOLECULAR ORIENTATION THERETO.